WHAT O2 SENSOR IS BANK 1, SENSOR 1

I have the 2.5 liter V-6. Engine check lite came on. Code reader says P0134 error, O2 sensor signal remains at center, BANK 1, SENSOR 1.
I only have 2 O2 sensors on car, 1 BEFORE catalytic convertor and one AFTER cat.

Which O2 sensor is BANK 1, SENSER 1?

I have replaced one BEFORE cat with OEM one, but still get same error code.
Also a few of my MONITOR test show on code reader as 'NOT COMPLETE' - how do I reset all monitors? Apparently all these monitors are RE-SET when ign. Key is turned off.
Thanks

The wiring diagram shows the car having 4 sensors. Bank one would be the rear bank and sensor one would be upstream.
Monitors are reset when the code is cleared and will not be ready until the car has been driven sufficiently to test all parameters and complete all cycles.